Method for monitoring insulation faults in an electric network and vehicle comprising an insulation fault monitor

Abstract

A method for monitoring an insulation fault in an electric network with at least one electric power system supplying electric power to one or more electric loads, and at least one insulation resistance monitor is provided, wherein the at least one electric power system includes at least one electrical power source, and wherein the at least one insulation resistance monitor monitors an insulation resistance between terminal leads of the at least one electric power source and at least one reference potential. The steps are performed of disconnecting the at least one electric power source from the one or more loads by opening each terminal lead; measuring the insulation resistance between the electric circuit of at least one electrical power source and the reference potential; measuring the insulation resistance for the total electric network; closing the second terminal lead with the first terminal lead open; and measuring the insulation resistance for the total electric network.

The invention claimed is: 
     
       1. A vehicle comprising
 at least an electric propulsion system powered by at least one electric power system, and 
 at least one insulation resistance monitor for monitoring an insulation fault in an electric network coupled to the electric propulsion system, wherein the at least one electric power system comprises at least one electric power source having terminal leads, and the vehicle comprises at least one reference potential, each terminal lead having a respective breaker for opening and closing the terminal lead, the electric power source and the insulation resistance monitor being disposed on a same side of the breakers for the terminal leads, and wherein the insulation resistance monitor is arranged to monitor the insulation fault by monitoring an insulation resistance between the terminal leads and the at least one reference potential, by 
 (i) disconnecting the at least one electric power source from the one or more loads by opening each terminal lead by opening the respective breakers for the terminal leads; 
 (ii) measuring the insulation resistance (R_isol 0 ) between the electric circuit of at least one electrical power source and the reference potential; 
 (iii) measuring the insulation resistance (R_isol 1 ) for the total electric network; 
 (iv) closing one terminal lead by closing the respective breaker for the one terminal lead with the other terminal lead open; and 
 (v) measuring a second insulation resistance (R_isol 2 ) for the total electric network. 
 
     
     
       2. The vehicle according to  claim 1 , wherein the at least one electric power source comprises at least one electrical storage device. 
     
     
       3. The vehicle according to  claim 1 , wherein the at least one electric power source comprises at least one fuel cell device. 
     
     
       4. The vehicle according to  claim 1 , wherein at least one breaker is provided for performing the method. 
     
     
       5. The vehicle according to  claim 1 , wherein the at least one breaker is arranged inside a casing of the at least one electric power source. 
     
     
       6. The vehicle according to  claim 1 , wherein the at least one breaker is coupled to an electric motor drive system. 
     
     
       7. The vehicle according to  claim 1 , embodied as an electric vehicle. 
     
     
       8. The vehicle according to  claim 1 , embodied as an embodiment as hybrid vehicle.